Drilled cooling air openings in gas turbine components

Abstract

A blade component of a gas turbine is disclosed around the outside of which hot air flows. The blade component is constructed as a hollow profile having outside walls and a tip cover, and having guiding walls arranged between the outside walls and connecting said outside walls. The blade component is cooled on the inside by cooling air flowing through cooling channels between the outside walls and the guiding walls. Cooling air flows through deflection areas in which the cooling air is deflected into flow stagnation zones. An efficient cooling of the blade component in the area of the stagnation zones is obtained in the area of the flow stagnation zones which are located at the outer corner of the deflection area. At least one drilled opening is provided in the outside wall through which drilled opening cooling air is able to flow at the stagnation zone from the cooling channel onto the outside of the blade component.

What is claimed is:  
     
       1. A rotor blade for a gas turbine comprising: a hollow blade having outside walls and a tip cover, and having first and second internal guide walls arranged between the outside walls, said first guide wall being located closer to a leading edge of said blade than said second guide wall and said second guide wall being located closer to a trailing edge of said blade than said first guide wall, said first and second guide walls each intersecting said tip cover, a central guide wall between the first and second guide walls, said central guide wall being spaced from said tip cover, thereby forming a cooling air passage extending in sequence between the first guide wall and the central guide wall and extending between the central guide wall and the tip cover and extending between the central guide wall and the second guide wall, the cooling air passage having flow stagnation zones adjacent the intersection between the tip cover and the respective first and second guide walls, and a plurality of openings drilled in an outside wall on the pressure side of the blade, said openings arranged in proximity to at least one of said flow stagnation zones and arranged at least next to the second guide wall in at least two rows, whereby cooling air is able to flow from the cooling air passage to the outside of the blade to obtain a more efficient cooling effect. 
     
     
       2. The rotor blade as claimed in  claim 1 , further including openings drilled in the tip cover and extending in a substantially radial direction relative to the rotation axis of the turbine rotor. 
     
     
       3. The rotor blade as claimed in  claim 2  wherein the tip cover has a tip extension on the outside of the tip cover adjacent said openings in the tip cover. 
     
     
       4. The rotor blade as claimed in  claim 1  wherein a guide rib is mounted in the hollow blade between the central guide wall and the tip cover. 
     
     
       5. The rotor blade according to  claim 1 , wherein: 
       at least one row of said openings is parallel to said guide wall.  
     
     
       6. The rotor blade accoding to  claim 1 , wherein: 
       the openings in the outside wall are arranged next to the second wall in two rows, with one row parallel to the second guide wall and one row parallel to the tip cover.  
     
     
       7. The rotor blade according to  claim 1  wherein: 
       the openings in the outside wall are arranged next ot the second guide wall in an entire area relative to one of said flow stagnation zones.  
     
     
       8. The rotor blade according to  claim 1 , wherein: 
       the openings in the outside wall are arranged next to the second guide wall in an entire area having a triangular shape relative to one of said flow stagnation zones.  
     
     
       9. The rotor blade according to  claim 1 , wherein the openings have the same diameter. 
     
     
       10. The rotor blade according to  claim 1 , wherein the openings have different diameters. 
     
     
       11. A rotor blade for a gas turbine comprising: a hollow blade having outside walls and a tip cover, and having first and second internal guide walls arranged between the outside walls, said first and second guide walls being spaced apart from each other and each intersecting said tip cover, a central guide wall between the first and second guide walls, said central guide wall being spaced from said tip cover, thereby forming a cooling air passage extending in sequence between the first guide wall and the central guide wall and extending between the central guide wall and the tip cover and extending between the central guide wall and the second guide wall, the cooling air passage having flow stagnation zones adjacent the intersection between the tip coever and the respective first and second guide walls, and a plurality of openings drilled in an outside wall on the suction side of the blade in proximity to at least one of said flow stagnation zones, whereby cooling air is able to flow from the cooling air passage to the outside of the blade to obtain a more efficient cooling effect. 
     
     
       12. A rotor blade for a gas turbine comprising: a hollow blade having outside walls and a tip cover, and having first and second internal guide walls arranged between the outside walls, said first and second guide walls being spaced apart from each other and each intersecting said tip cover, a central guide wall between the first and second guide walls, said central guide wall being spaced from said tip cover, thereby forming a cooling air passage extending in sequence between the first guide wall and the central guide wall and extending between the central guide wall and the tip cover and extending between the central guide wall and second guide wall, the cooling air passage having flow stagnation zones adjacent the intersection between the tip cover and the respective first and second guide walls, and a plurality of openings in an outside wall arranged in proximity to at least one of said flow stagnation zones, the openings are cylindrical and extend perpendicular to the outside wall, the openings being spaced apart from each other by at least one diameter of the openings, and being arranged in rows, the openings being spaces at least 5 diameters of the openings from the tip cover and the openings being located adjacent the second guide wall, whereby cooling air is able to flow from the cooling air passage to the outside of the blade to obtain a more efficient cooling effect. 
     
     
       13. The rotor blade as claimed in  claim 12  wherein the openings include a conical portion adjacent the outside of one of the outside walls.